refactor: redesign notebook cell dimensions and responsive views

[emrberk]

Summary

• Replace grid height and maximized-view agent semantics with independent editor_height, result_height, and view controls.
• Preserve preferred view intent while reporting the effective responsive view and compact/wide tier.
• Make cell resizing, compact transitions, result minimums, and the editor visibility toggle consistent across notebook UI states.
• Return faithful JSON previews, preserve semantic dimensions in snapshots, and clarify duplicated result snapshot behavior.

Validation

• npm run typecheck
• npm run test:unit (2,012 tests)
• focused notebook snapshot/tool tests (141 tests)
• npm run build
• targeted ESLint and git diff --check

Deferred follow-up

• Update mcp-server-questdb for the new notebook tool contract.
• Bump the MCP server version.
• Update EXPECTED_MCP_VERSION in this repository after that release.